This application claims the priority of German patent application Serial No. 199 13 427.7 filed Mar. 25, 1999. The disclosure of the above-referenced German patent application, as well as that of each U.S. and foreign patent and patent application mentioned in the specification of the present application, is incorporated herein by reference.
The invention relates to improvements in apparatus for manipulating sections of rod-like filters for tobacco smoke, and more particularly to improvements in apparatus for transferring sections of rod-like filters which contain pulverulent, granular and analogous solid ingredients, such as charcoal.
It is often necessary to transport rod-like filters for tobacco smoke (hereinafter called filters for short) between two spaced-apart locations, particularly between a sender (such as a filter rod maker) which is set up to deliver successive filters of a short or long series of filters lengthwise into a pneumatic conveyor for transport to a receiving station, e.g., to the magazine of a filter tipping machine. Such apparatus are often equipped with arrangements which are designed to intercept, collect and dispose of solid particles which become separated from the rod-like filler (such as a filler consisting of crepe or acetate fibers). In the absence of any undertakings to the contrary, stray particles of charcoal or the like which become separated from filters in the pneumatic conveyor are likely or bound to contaminate the conveyor and/or the receiving station to an extent which necessitates temporary stoppages of the apparatus in order to carry out a cleaning operation or to permit a restarting of the apparatus.
Moreover, loose particles of charcoal or the like tend to adhere to the external surfaces and to thus contaminate the tubular wrappers of the filters.
Attempts to gather stray particles of charcoal or the like in apparatus which are designed to transport rod-like filters for tobacco smoke are disclosed, for example, in commonly owned British patent specification No. 1 410 473 (published Oct. 15, 1975) and in the U.S. Pat. No. 5,556,236 granted Sep. 17, 1996. The aforementioned patents share the feature that an arcuate section of the pneumatic conveyor is provided with an opening for the evacuation of solid particles which escape from the rod-like fillers of the filters and/or become separated from the external surfaces of the tubular envelopes for the fillers. The solid particles can be selected to enhance the tobacco smoke filtering action and/or to enhance the flavor of tobacco smoke furnished by a lighted filter cigarette, cigar or cigarillo.
Certain presently known filter lines which are capable of introducing particles of charcoal or the like into the fillers of acetate fibers or the like are known as AC 2 and AC 3 (both distributed by the assignee of the present application). The operation of each of these AC machines is based on the principle that charcoal is fed into a collector where it stays until a demand signal from a reservoir initiates a feed operation. Each AC machine cooperates with a filter rod making machine (e.g., a machine known as KDF and distributed by the assignee of the present application), and each filter rod making machine can be equipped with means for aspirating stray granules off the so-called garniture of the filter rod making machine by resorting to a so-called extraction hood which returns the aspirated granules to the source by way of a pipeline or the like.
An object of the present invention is to provide an apparatus which can transport rod-like filters for tobacco smoke in such a way that all or nearly all loose solid particles (such as charcoal granules) advancing with the filters from a sender to a receiving station can be intercepted, collected and disposed of (e.g., reused) with a higher degree of reliability than in heretofore known apparatus.
Another object of the invention is to provide a novel and improved pneumatic conveyor for use in the above outlined apparatus.
A further object of the invention is to provide an apparatus which prevents pronounced and/or long-lasting frictional engagement between the external surfaces of tubular wrappers of rod-like filters for tobacco smoke and stray particles of charcoal and the like.
An additional object of the invention is to provide a novel and improved module which can be utilized to convert a conventional filter manipulating apparatus into a superior apparatus capable of intercepting and gathering much higher percentages of loose solid particles of charcoal and the like.
Still another object of the invention is to provide a novel and improved method of intercepting, gathering and evacuating loose particles of charcoal or the like from apparatus for transporting and/or otherwise manipulating rod-like filters for tobacco smoke.
A further object of the invention is to provide a rod-like filter for tobacco smoke which is produced in the above outlined novel apparatus and/or in accordance with the above-outlined method.
One feature of the present invention resides in the provision of an apparatus for transporting tobacco smoke filtering rods, which carry solid particles (such as charcoal granules), along an elongated path extending from a sender (such as a filter rod maker) to a receiving station (e.g., into the magazine of a filter tipping machine).
The improved apparatus comprises a pneumatic conveyor defining an elongated path for lengthwise advancement of successive filtering rods of a file of filtering rods by means of a pressurized pneumatic fluid (such as compressed air) in a direction from the sender to the receiving station. The conveyor comprises a section which is located downstream of the sender, which extends along an arc of less than 180xc2x0 (for example, along an arc which equals or approximates 90xc2x0), and which is arranged to advance successive filtering rods from a lower level to a higher level. The conveyor section has an at least substantially sealed arcuate upper side and an at least partially open arcuate underside, and the improved apparatus further comprises a cover which overlies the underside of the conveyor section and is arranged to permit expulsion of loose solid particles from the elongated path into a chamber of a collecting device but to interfere with appreciable flow of pressurized gaseous fluid from the conveyor section into the chamber of the collecting device.
The conveyor section is or can be adjacent (e.g., closely or very closely adjacent) the sender.
The internal surface of the conveyor (such as an elongated conduit) has an internal surface which can include a convex portion at the upper side and a concave portion at the underside of the conveyor section.
The cover is or can be elongated and can include a first end portion and a second end portion at a level above the first end portion; one of these end portions (preferably the upper end portion) is or can be provided with a lug, flap or an analogous deflector for gaseous fluid.
The cover can have a concavo-convex shape, and its concave side can confront the underside of the conveyor section. For example, the cover can be made (at least in part) of metallic sheet material and can be precurved at the locus of manufacture.
An upper end portion of the aforementioned collecting device can be installed downstream of the lower end portion (as seen in the direction of advancement of filtering rods from the sender to the receiving station), and the lower end portion can be provided with at least one outlet for collected solid particles.
The at least one outlet can define at least one compartment having a particle receiving portion and a particle discharging portion. A first open-and-shut valve can be employed and actuated to connect the receiving portion of the compartment with the chamber of the collecting device, and a second open-and-shut valve can be provided and actuated to permit and interrupt evacuation of solid particles from the discharging portion of the compartment. Alternatively, the at least one outlet can include automatically operable valve means serving to establish and to interrupt communication between the chamber of the collecting device and the at least one compartment of the outlet. For example, the automatically operable valve means can include means for permitting and interrupting evacuation of solid particles from the at least one compartment. Such valve means can be arranged to regulate the admission of solid particles into and the evacuation of solid particles from the at least one compartment as a function of time.
The aforementioned conveyor section can form part of a prefabricated module, preferably a mobile module. The conveyor section which forms part of such mobile module can be detached from and separably connected to additional sections of the conveyor.
The receiving station can include a magazine or other suitable means for temporarily storing at least one supply of filtering rods.
The sender can include means for pneumatically propelling filtering rods into an inlet of the pneumatic conveyor upstream of the aforementioned conveyor section (as seen in the direction of advancement of filtering rods toward the receiving station). Furthermore, the sender can include means for advancing filtering rods in several directions, for example, first (e.g., downwardly) along an at least substantially vertical path and thereupon along a substantially horizontal path.
The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved apparatus itself, however, both as to its construction and the modes of assembling and operating the same, together with numerous additional important and advantageous features and attributes thereof, will be best understood upon perusal of the following detailed description of numerous presently preferred specific embodiments with reference to the accompanying drawings.